Garmin GNC 420W Pilots Guide - Page 33

SECTION 2 COM Selecting a COM frequency for any airport in the database: 1) Turn the large right knob to select the WPT Page Group. 2) Turn the small right knob to select the Airport Frequencies Page (Figure 2-9). Emergency Channel The GNC 420's emergency channel select provides a quick method of selecting 121.500 MHz as the active frequency in the event of an in-flight emergency. Emergency channel select is available anytime the unit is on, regardless of GPS or cursor status, or loss of the display. To quickly tune and activate 121.500: Press and hold COM Flip-flop Key (or COM Remote Tranfer Switch) for approximately two seconds (Figure 2-10). Figure 2-9 Airport Frequencies Page 3) Press the small right knob to place the cursor on the airport identifier field. 4) Use the small and large right knobs to enter the identifier of the desired airport. Press the ENT Key when finished. 5) Turn the large right knob to highlight the desired frequency. 6) Press the ENT Key to place the highlighted frequency in the standby COM Window field. Figure 2-10 Emergency Channel Active If the COM Remote Transfer switch is used to select the emergency channel, further changes in COM frequency will not be possible without momentarily pressing the COM Remote Tranfer Switch again, or by recycling power. NOTE: Under some circumstances if the COM system loses communication with the main system, the radio will automatically tune to 121.500 MHz for transmit and receive, regardless of the displayed frequency. 190-00140-20 Rev. K GNC 420(A) Pilot's Guide and Reference 2-5